Aromatic-turmerone induces neural stem cell proliferation in vitro and in vivo

Introduction: Aromatic (ar-) turmerone is a major bioactive compound of the herb Curcuma longa. It has been suggested that ar-turmerone inhibits microglia activation, a property that may be useful in treating neurodegenerative disease. Furthermore, the effects of ar-turmerone on neural stem cells (NSCs) remain to be investigated. Methods: We exposed primary fetal rat NSCs to various concentrations of ar-turmerone. Thereafter, cell proliferation and differentiation potential were assessed. In vivo, naive rats were treated with a single intracerebroventricular (i.c.v.) injection of ar-turmerone. Proliferative activity of endogenous NSCs was assessed in vivo, by using noninvasive positron emission tomography (PET) imaging and the tracer [F-18]-fluoro-L-thymidine ([F-18] FLT), as well as ex vivo. Results: In vitro, ar-turmerone increased dose-dependently the number of cultured NSCs, because of an increase in NSC proliferation (P < 0.01). Proliferation data were supported by qPCR-data for Ki-67 mRNA. In vitro as well as in vivo, ar-turmerone promoted neuronal differentiation of NSCs. In vivo, after i.c.v. injection of ar-turmerone, proliferating NSCs were mobilized from the subventricular zone (SVZ) and the hippocampus of adult rats, as demonstrated by both [F-18] FLT-PET and histology (P < 0.05). Conclusions: Both in vitro and in vivo data suggest that ar-turmerone induces NSC proliferation. Ar-turmerone thus constitutes a promising candidate to support regeneration in neurologic disease.